msm: ADSPRPC: Fix memory leak for remote heap

Fix the condition that was causing the remote heap from
not being freed.

Change-Id: I825e813f4f4e7c3cecaf9150d9ef40ff40cfb5a2
Acked-by: Bharath Kumar <bkumar@qti.qualcomm.com>
Signed-off-by: Sathish Ambley <sathishambley@codeaurora.org>